This application is based on Patent Application No. 2001-034554 filed Feb. 9, 2001 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an ink jet printing apparatus, an ink information detecting apparatus, and an ink information detecting method.
2. Description of the Related Art
In recent years, a market has been expanded for ink jet (IJ) printing apparatuses for use in offices, homes, and the like. However, these printing apparatuses can no longer perform printing operations once ink as a printing material is used up. On the other hand, with a laser beam-based printing apparatus (LBP), a printed image starts to appear lighter when toner as a printing material is almost used up, thereby allowing a user to determine when to refill the apparatus with toner. Thus, it is more important for ink jet printing apparatuses to accurately detect the amount of remaining ink as a printing material than for LBPs or general-purpose copiers.
As a method of detecting the amount of ink remaining in an ink jet printing apparatus, a method has been proposed which uses an ink tank the interior of which can be seen from the outside thereof so that a user can check the amount of ink remaining in the ink tank. A specific example includes a construction in which a part of the ink tank is made transparent as described in Japanese Patent Application Laying-open No. 5-42680 (1993) or a construction in which ink is accommodated directly in a part of an ink chamber so that the amount of remaining ink can be checked from the outside as described in Japanese Patent Application Laying-open No. 6-286160 (1994). Further, Japanese Patent Application Laying-open No. 6-226989 (1994) describes a method of optically determining the amount of ink that decreases step by step by dividing the ink chamber into a number of parts. Furthermore, Japanese Patent Application Laying-open No. 5-309922 (1993) describes a method of detecting the amount of remaining ink each time a predetermined printing operation is performed. That is, this publication describes a method of using a serial scan method to cause a print head to print an image corresponding to one line on a print sheet, using a presence detecting sensor to detect a partial image of the printed image, and determining the amount of remaining ink on the basis of the result of the detection. Moreover, Japanese Patent Application Laying-open No. 6-270410 (1994) describes a method of detecting ink using electrodes.
Methods have also been proposed in which the main body of the printing apparatus detects the amount of ink remaining in the ink tank in order to determine the amount of remaining ink to give a warning or to limit the printing operation. For instance, Japanese Patent Application Laying-open No. 6-320751 (1994) describes a method of counting the number of ink dots formed on a printed medium and detecting the amount of remaining ink on the basis of the counts. Further, Japanese Patent Application Laying-open No. 11-334107 (1999) describes a method of detecting the amount of remaining ink by taking into consideration the size of ink dots. These methods count the number of ink dots, and calculates the amount of remaining ink on the basis of this dot count information. In contrast with a method of directly detecting ink in a container such as a tank that accommodates the ink, these dot count methods of calculating the amount of remaining ink on the basis of the dot count information are also called xe2x80x9cremaining amount estimating methodsxe2x80x9d because the mathematically estimate the amount of remaining ink.
In the method of detecting the amount of remaining ink on the basis of such a dot count method, because of a variation in the amount of ink ejected per dot from the print head, it is unavoidable that a certain error occurs in detection of the amount of remaining ink. To solve this problem, Japanese Patent Application Laying-open No. 9-169118 (1997) and U.S. Pat. No. 6,151,039 describe methods comprising detecting means of a mechanical construction which is operated using a switch when the amount of remaining ink reaches a predetermined value, to correct a dot count value when the detecting means performs a detecting operation.
As described above, the various methods have been proposed as methods of detecting the amount of remaining ink. In connection with the aspect of manufacture of print heads, it is unavoidable that the amount of ejected ink varies, and this variation leads to an error in detection of the amount of remaining ink on the basis of the dot count method. As a result, even if the number of dots is counted accurately, an error is involved in the ink consumption calculated using the count. Further, if the count of the dot number is corrected when the detecting means of a mechanical construction performs a detecting operation, as proposed by Japanese Patent Application Laying-open No. 9-169118 (1997), then the count is not corrected until the detecting means of a mechanical construction performs a detecting operation, and thus still contains an error. Furthermore, none of the above described publications describe the use of a corrected value such as the count of the dot number for purposes other than the detection of the amount of remaining ink.
It is an object of the present invention to provide an ink jet printing apparatus, an ink information detecting apparatus, and an ink information detecting method which can calculate the ink consumption without any errors by combining two detecting means.
The present invention provides an ink jet printing apparatus that prints an image on a print medium by using a print head that can eject ink fed from an ink tank, the ink jet printing apparatus comprising estimating means for mathematically estimating ink consumption on the basis of driving conditions for the print head, detecting means for detecting that the amount of ink remaining in the ink tank has decreased to a predetermined value, and correcting means for correcting a value used by the estimating means to calculate the ink consumption, on the basis of results of detection by the detecting means.
The present invention provides an ink information detecting apparatus that detects information on ink fed from an ink tank to a print head that can eject ink, the ink information detecting apparatus comprising estimating means for mathematically estimating ink consumption on the basis of driving conditions for the print head, detecting means for detecting that the amount of ink remaining in the ink tank has decreased to a predetermined value, and correcting means for correcting a value used by the estimating means to calculate the ink consumption, on the basis of results of detection by the detecting means.
The present invention provides an ink information detecting method of detecting information on ink fed from an ink tank to a print head that can eject ink, the method comprising the steps of mathematically estimating ink consumption on the basis of driving conditions for the print head, and correcting a value used to calculate the ink consumption, on the basis of results of detection of the amount of ink remaining in the ink tank.
The present invention provides an ink jet printing apparatus that prints an image on a print medium by using a print head that can eject ink fed from an ink tank, the apparatus comprising count means for counting the number of operations that consume ink, the operations including printing operations, detecting means for detecting that the amount of ink remaining in the ink tank has decreased to a predetermined value, remaining amount calculating means for calculating the amount of ink remaining in the ink tank on the basis of the value counted by the count means as well as a unit consumption corresponding to the operations after the detecting means has detected that the amount of ink remaining in the ink tank has decreased to the predetermined value, and correcting means for correcting the unit consumption on the basis of the count indicated by the count means when the detecting means has detected that the amount of ink remaining in the ink tank has decreased to the predetermined value, and wherein the calculating means calculates the amount of remaining ink on the basis of the unit consumption corrected by the correcting means.
The present invention provides a method of calculating the amount of ink in ink tank in an ink jet printing apparatus that prints an image on a print medium by using a print head that can eject ink fed from an ink tank, the method comprising the steps of counting the number of operations that consume ink, the operations including printing operations, detecting that the amount of ink remaining in the ink tank has decreased to a predetermined value, correcting a unit consumption used to calculate the amount of remaining ink, on the basis of the count obtained at the counting step when the detecting step has detected that the amount of ink remaining in the ink tank has decreased to the predetermined value, and after the detecting step has detected that the amount of ink remaining in the ink tank has decreased to the predetermined value, counting the number of operations that consume ink, the operations including printing operations, and calculating the amount of ink remaining in the ink tank on the basis of the unit consumption corrected by the correcting step.